1. Field of the Invention
The present invention relates to a knitting yarn feeding apparatus for a flat knitting machine capable of knitting a texture similar to that of warp knitting by using a flat knitting machine for weft knitting.
2. Description of the Related Art
The prior art of the present invention includes Japanese Examined Patent Publication JP(B2) 51-42225 (U.S. Pat. No. 3,733,856, GB 1353531) filed by the present applicant, or the flat knitting machine (model name SPL-C092FF) manufactured by the applicant.
The flat knitting machine of the above-mentioned type comprises a knitting yarn feeding apparatus which not only feeds knitting yarn to needles with a feeder tube reciprocating on knitting yarn guide rails erected above nozzles between front and rear needle beds, but also enables to form a warp knitting texture through an arbitrary number of feeder tubes for feeding knitting yarn to knitting needles in the needle beds confronting at an upper position of either one of the front and rear needle beds. This knitting yarn feeding apparatus comprises a device which makes it possible that the knitting yarn feeding apparatus oscillates in the vertical direction in order to wind knitting yarn on the confronting knitting needles, and moves in the longitudinal direction of the needle beds.
Knitting by the use of the above-mentioned knitting yarn feeding apparatus capable of forming a warp knitting texture will be briefly described. First, an arbitrary number of knitting needles are advanced above the nozzle, on a needle bed, by passing a cam box of a carriage. In the advanced state of the knitting needles, the knitting yarn feeding apparatus above the confronting needle bed is oscillated from the descending position to the ascending position by passing each feeder tube by the knitting needle side at the advanced position (knitting yarn feed start position). Then the feeder tubes are moved by the portion of a desired number of knitting needles in the same direction as the advancing direction of the succeeding cam box, and are passed again by the knitting needle side to oscillate to the descending position (knitting yarn feed end point). By this action, the knitting yarn is wound about the body of the knitting needle located between the knitting yarn feed start position and the knitting yarn feed end position. In this state, the cam box runs and the knitting needle at the advanced position retreats, and the knitting needle is retracted to form a stitch. Such knitting is repeated, and by feeding knitting yarn in a zigzag form while adjusting the stroke of the feeder tubes in the transverse direction, so that a desired pattern is formed.
That is, as shown in FIG. 18, two groups of feeder tubes 3, 4 are provided in order to feed knitting yarn 2 to plural knitting needles 1 in one needle bed, for example, the front needle bed. From the plural feeder tubes 3 of one of the two groups, yarns 5 of the same color or different colors are supplied as warps. In order to feed knitting yarn 2 as warps in such a manner, it requires the lapping motion that the feeder tubes 3, 4 are oscillated onto the knitting needles 1 at pitches of one or plural knitting needles 1 in relation to horizontal directions L, R, and the swing motion that the feeder tubes 3, 4 cross vertically among the knitting needles 1. In the above-mentioned prior art, plural feeder tubes 3, 4 are mounted on one and the same board, which is externally driven so that the lapping motion and swing motion are generated. The lapping motion is generated by displacing the board in the longitudinal direction of the needle bed along the axis for the swing motion by a link mechanism. In another prior art, lapping motion is effected by using a ball screw or a linear motor.
In the above-mentioned prior art, driving for providing the feeder tubes with the swing motion and driving for providing the feeder tubes with the lapping motion are performed externally by using different mechanisms, and therefore it is necessary to allow the displacement of the board caused by one driving when the other driving is being carried. The mechanisms are fixed to the frame of the flat knitting machine, and therefore a flexible mechanism such as push rod is needed for transmission mechanism of driving force. That is, the swing motion and lapping motion of the feeder tubes are achieved by the mechanisms provided at the frame side of flat knitting machine, and it is required to cope with deflection, if occurring, by using push rod or the like.
In the knitting yarn feeding apparatus of the prior art, however, when it is desired to extend the stroke which is a displacement of the lapping motion, the length of the shaft for swing motion or ball screw or linear motor must be extended, and the mechanism for lapping motion may not settle within the overall width of the flat knitting machine. Besides, since lapping motion or swing motion is effected entirely on the plural feeder tubes, it is hard to adjust the motion range of the distortion stroke.